*{
    margin: 0px;
    padding: 0px;
}
.top{
    width: 100%;
    height: 50px;
    background-color: black;
}
.top_content{
    width: 75%;
    height: 50px;
    margin: 0px auto;
    background-color: blue;
 
 }
.body{
    margin: 0px auto;
    width: 75%;
    height: 1500px;
    background-color: chartreuse;
}
.body_img{
    width: 100%;
    height: 400px;
    background-color: aqua;
}
.body_content{
    width: 100%;
    height: 1100px;
    background-color: brown;
 
}
.body_no{
    width: auto;
    height: 50px;
    background-color: blueviolet;
}
.footing{
    width: 75%;
    height: 400px;
    background-color: darkcyan;
    margin: 0px auto;
}
.foot_content{
    width: 100%;
    height: 350px;
    background-color: darkgreen;
}
.foot_subnav{
    width: 100%;
    height: 50px;
    background-color: dodgerblu；
}